Process control plants or systems often employ rotary valves, such as ball valves, butterfly valves, eccentric-disk valves, eccentric-plug valves, etc., to control the flow of process fluids. Rotary valves typically include a fluid control element (e.g., a disk, a ball, etc.) disposed in the fluid path and rotatably coupled to the body of the valve via a shaft. To control the flow of fluid through some rotary valves, the position of the fluid control element may be varied from a closed position at which the fluid control element is in sealing engagement with a seal that surrounds a flow aperture to a fully open or maximum flow rate position at which the fluid control element is spaced away from the seal.
To enable the fluid control element to properly align with the seal, some rotary valves are provided with opposing sleeves that respectively abut an upper drive hub and a lower drive hub of the fluid control element. Additionally, to enable the fluid control element to properly align with the seal, some rotary valves include a shaft that extends through both the upper and lower drive hubs of the fluid control element into the fluid path and through the respective sleeves. While such an approach may enable alignment of the fluid control element relative to the seal, in sanitary applications, the numerous components and abutments within the fluid path associated with this approach tend to cause particulate and/or bacteria accumulation and/or growth on and/or adjacent to these components.